[time-nuts] Three Phase Power

NeonJohn jgd at neon-john.com
Tue Jun 28 17:21:05 UTC 2011



On 06/28/2011 08:16 AM, Will Matney wrote:

> Things like this, make me think, that these smart meters need to be
> policed, if we don't want to end up being royaly screwed. Making sure the
> timing is correct, on any of the meters, is the same as demanding
> calibration for any piece of equipment like scales, etc, and it ought ot be
> done more, since money changes hands.

Being a former utility engineer and a closet meter nut (anyone else have
a revenue meter calibration bench in his lab? :-), I thought I'd comment
on this.

Federal regulations require that smart meters be manually read once a
year.  That will re-sync things if the electronic reportage gets out of
whack.

That solves only one of the many problems with electronic meters.  Let's
say lightning hits hard enough to blow the meter apart.  With the old
mechanical meters, at least a last reading could be taken from the
mechanical register.  With the electronic meter, if the LCD is even
still intact, it's just laying there blank.

A client utility recently rolled out about 80,000 electronic meters with
no pilot program or prior testing.  It has been an unmitigated disaster.
 Over 10% initial failure rate, probably from infant mortality.
Automatic reading has been spotty at best.  The selected system uses a
ZigBee-based mesh network which in a rural setting doesn't work very
well.  The utility has has to hire a contractor to handle customer
complaints.

I got a batch of 100 of the old decommissioned mechanical meters.  I
wanted to test them to see how accurate they are.  Some are over 30
years old.  I'm about half way through the batch and have yet to find
one more than about 1.5% out.  This is what I expected from past experience.

The electrical Co-Op that serves me did it the smart way.  They deployed
the Turtle system.  This is a system that retrofits to the mechanical
meter with a photocell to count wheel revolutions.  It sends the reading
back over the power line using a modulation scheme that I have yet to be
able to discover.  They're pretty tight lipped about that.

>From what I hear from talking to the field engineers, this has been a
highly successful roll-out with very few complaints.

John

-- 
John DeArmond
Tellico Plains, Occupied TN
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